1. Technical Field
The present invention relates to rotors for electric rotating machines that are used in, for example, motor vehicles as electric motors and electric generators, and to methods of manufacturing the rotors.
2. Description of Related Art
There is known, for example from Japanese Unexamined Patent Application Publication No. 2007-236019, a rotor for an electric rotating machine that is designed to be used in a motor vehicle. The rotor includes a rotor core, a plurality of magnets, a plurality of filler members and first and second end plates. The rotor core is fixed to a rotating shaft and has a plurality of magnet-receiving holes formed therein. Each of the magnets is received in a corresponding one of the magnet-receiving holes of the rotor core. Each of the filler members is provided in a corresponding one of the magnet-receiving holes of the rotor core to fill the void spaces unoccupied by the corresponding magnet. The first end plate is arranged on one axial side of the rotor core and fixed to the rotating shaft. The second end plate is arranged on the other axial side of the rotor core and fixed to the rotating shaft with a lower fixing strength than the first end plate.
Further, in the above rotor, the magnets are arranged in the corresponding magnet-receiving holes of the rotor core so as to be in direct contact with the first end plate while having the filler members interposed between the magnets and the second end plate. Consequently, with the direct contact between the magnets and the first end plate, heat generated by the magnets during operation can be removed from the magnets via the first end plate. As a result, the performance of the rotor for dissipating heat from the magnets can be improved.
In general, if the heat generated by the magnets during operation could not be sufficiently dissipated from the magnets, the magnetic force of the magnets would be lowered.
Therefore, it is desired to more effectively dissipate the heat generated by the magnets during operation from the magnets, thereby more reliably preventing the magnetic force of the magnets from being lowered.